Incandescent electric lamp.



F. & F; L. HARRISON. INCANDESCENT ELECTRIC LAMP.

APPLICATION FILED on. 24. 1913.

Patented NOV. 21, 1916.

zmwro/rs FRANCIS HARRISON AND FRANCIS LESLIE HARRISON, 0F PRESTWICK. SCOTLAND.

'INCANDESCENT ELECTRIC LAMP.

Specification of Letters Patent.

Patented Nov. 21, 1916.

Application filed October 24, 1913. Serial No. 797,061.

To all whom it may concern:

Be it known that We, FRANCIS HARRISON and FRANCIS LESLIE HAmusoN, citizens of the United Kingdom of Great Britain and Ireland,and residents of Pegu,Marina Road, Prestwick, Ayrshire, Scotland, have invented certain new and useful Improvements in or Relating to Incandescent Electric Lamps, of which the following is a specification, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to incandescent electric lamps of the metallic filament type, in contradistinction to carbon filament lamps, and relates more particularly to the means and method of attachment of the fila- .ments in place and to the provision of such means as w1ll permit of a ready and cheapreplacement or renewal of a broken filament, while retaining the original cap, bulb and filament support.

According to one form of our improved method, applied to metal filament lamps, we employ in connection with the usual leading-in wires, supporting wires having their ends bent into a spiral so as to grip the end of the filament, and in the case of two of them to grip the leading'in wire as well. Further in connection with such spring gripping means we prefer in some cases to apply them at the pip end of the lamp and to bring the leading-in wires down the central stem, so as to facilitate renewal when a filament breaks, as will he explained.

VVewill now describe, with reference to the accompanying drawing, a lamp, accord ing to this invention, comprising central downwardly extending leadingsin conducting wires and the spring supporting wires for receiving'the ends of the filaments and leading-in wires.

Figure 1 is an elevation of the lamp. Figs. 2 and 3 are detail views, and Fig. 4 shows a modified form of filament securing arm.

The central filament supporting portion instead of being made of a short length of tube, through which the leading-in wires pass and project laterally, and a central extension glass rod, to the lower end of which are secured the radial supports for the lower ends of the filaments, is made of one piece of glass tube forming the central through which the conducting wires 6 pass and join the inner part of the leading-in support a,

wires 7) which issue at the lower end of said support. At the upper end of the tube we form a collar or flange 0 from which extend outwardly a series of supporting arms d, here shown as straight wires with hooked ends 0? for receiving the upper parts of the filaments. Near to its lower end the tube a is provided with a series of outwardly extending filament-supporting wires a bent at their outer ends in the form of spirals 6 adapted to clamp or pinch the ends'of the filaments and also the ends or outer part of the leading-in wires in the case of two of them between their bent portions.

In the construction illustrated inverted V-shaped or. hairpin filaments f are en1- ployed, the filaments being simply hung onthe hooks (1 while their lower ends are gripped between the bends or spirals of the lo ersupports e. For this purpose the latter are preferably provided with ends e projecting parallel with the wire 6' to act as arms for opening the spring spirals by pressing e and 6 together, as shown more clearly in the plan views in Fig. 2 showing the spring in its closed position, and in its open position, 2'. 6. when 0 and e are pressed together.

The two leading in wires 6'' are similarly secured to two of the supports so that the circuit through the filaments is completed. The lower end of the tube a may be pinchedor flattened. Itwill thus ,be seen that in this construction themetallic filament 1s upside down or reversed as com pared with ordinary filament lamps, theobject of this arrangement being that should a filament break in use, the lamp can be more easily repaired as will be explained, than would be the case if the ends of the filaments were secured at the cap end of the lamp. To effect such a repair or renewal, the pip on the lamp bulb is removed and air is allowed to enter the bulb. The hole 9 is then enlarged, say by means of a gas flame, and the fractured filament or filaments removed, and the inner surface of the-bulb cleaned if necessary, which can be done by heating the outside of the glass by means'of a Bunsen flame. A new filament is then introduced through the hole 9 by means of a suitable instrument and the bend of the filament hung on the hook they are correctly positioned against their respective supports e, the outer part of the bent or s iral portions e of the latter are the filament 1s firmly gripped to its suprt. Alternatively the parts 6 and e may ii forced apart, as shown in Fig. 8, in which case the inner portion of the spiral will be opened to secure the filament. At 1 in Fig. 4 we have shown a slightly modified construction, the wire support having a hook e, at its outer end so that on inserting a rod in the hook e' 'the spire of the spiral can be opened out to receive the filament. A piece of glass tube is then fused to the of the holes y and the bulb is then ilfiusted and finished off, in the usual 'we 1 known manner.

As metal filaments are usually extremely thin and consequently somewhat ditlicultto a see, we prefer to dip the ends of,the filament mto some coloring matter,-such as sealing wax, sothat the ends of the filament may be easily located, when they are being secured-in place, after which the ends, below the support, carrying the sealing wax are broken off.

The-central support may be of an de sired slia or cross section and may of clear white or colored glass or it may be silvered .to act as a. reflector, the leading in or tonducting wires within it being thus,

hidden from view, and while a tube is probably the simplest and most convenient device for bringin the leadin -in wires to the lower part 0 the lamp, t ey could obviously be embedded in glass or other nonconducting material or arranged in grooves in a glass, kaolin or like rod or support, or be carried down the outside of the suprt. while we have referred to hairpin filaflexible metal filament which is bent overthe hooked supports at the ca end of the lamp and then secured to the support and so on.

In soilne filases, flor instalfioe when com- )arative t ick fi aments or carrym' a heavy cui rent are used, we,may attach to the end of the filament a iece of conducting wire, which in turn is secured to the spring su'pporting wire.

While we have Stab? thaththe hole} fgr repair urposesismaeatte i o te bulb, it izan be made at another piiri if such would be more advantageous for easy access to the particular part to be renewed.

What we claim and desire to secure by Letters Patent is:-

1. In an electric lamp, the combination of a leading-in wire' a support supported by the lamp se arately from said wire and having a coil ormed therein grip ing said will-e; and a filament also grip by said 001 2. In an electric lamp, the combination of a leading-in wirea support supported by the lamp separately from said wire and havin a coil formed therein wire between adjacent convolutions; and'a filament also gri ped between adjacent convolutions of said coil 3. In an electriclamp, the combination of a leading-in wire; a gripping support sup ported by the lamp separately from said wire and havin a coil formed therein gripping said wire tween its convolutions and iavmg an extension at its free end for ma nipulatlng the gri ping support; and a filament also grippe between convolutions of said coil,

In witness whereof we have hereunto set our hands in presence of two witnesses.

FRAgCIS HARRISON. FRA CIS LESLIE HARRISON.

Witn:

Taacr LAY, O. J. WORTH.

ower spring 

